Apparatus and method for molding circular concrete tanks



Jan. 27, 1948. F. PARRETT 2,435,052

v APPARATUS AND METHOD FOR MOLDING CIRCULAR CONCRETE TANKS Filed April 7, 1944 Patented Jan. 27, 1948 APPARATUS AND METHOD FOR MOLDING CIRCULAR CONCRETE TANKS Frank Parrett, Arapaho, Okla.

Application April 7, 1944, Serial No. 529,982

4 Claims. 1

This invention relates to a novel method of constructing circular open-top concrete water tanks and the like, and to a novel apparatus therefor.

The primary object of the invention is to eliminate the need of erectin molds in constructing circular concrete or like tanks, thereby expediting the work and reducing the labor and expense thereof.

Another object is to provide a simple and efficient apparatus or device for smoothing the inner and outer surfaces of the circular wall and the upper surface of the bottom wall of a tank as the construction of the tank proceeds according to the present method.

Other objects and advantages of the present invention will become apparent from the following description, when considered in connection with the accompanying drawing.

In the drawing:

Figure 1 is a top plan View of a partially completed tank being constructed in accordance with the method and by use of the apparatus embody- -ing the present invention; and

Figure 2 is an enlarged fragmentary vertical section taken on line 2-2 of Figure 1.

In the illustrated embodiment, a circular recess 5 has been formed in the surface of the ground, corresponding to the desired diameter of the base of the tank and a radial drain pipe 6 has been laid substantially horizontally in the ground to extend from the center of the recess 5 to a point outwardly beyond the periphery of the recess. The inner endof drain pipe 6 has a vertical extension I of a length greater than the height of the tank to be constructed and located centrally of the recess 5. If the circular wall of the tank is to be reinforced, as preferred, vertical rods 8 have their lower ends set in the ground within and adjacent the periphery of the recess 5 so that they will be located in the circular wall of the tank, intermediate the inner and outer surfaces thereof, when said wall is erected. A circular strip of wire mesh fabric 9 is then placed about and anchored to the rods 8.

By means of a trowel or the like, a layer of concrete of mortar-like consistency is then placed on the ground at the margin of the recess 5, this layer being of several inches in height and roughly approximately the desired thickness of the circular wall of the tank. A rotatable smoothing device, to be presently described and using the drain pipe extension I as its axis of rotation, is then rotated entirely about the recess 5 so as to smooth the inner and outer surfaces of the layer by removing some excess material and trowelling some of it into any depressions left in the surfaces. Other layers are then successively applied, one upon the other, and smoothed in-the same way, until the circular wall ID is of the desired height. Also, concrete is placed in the recess to form the bottom wall II of the tank, and the upper edge of the circular wall Ill and the upper surface of the bottom Wall II are shaped and smoothed by use of the smoothing device. The smoothing device is then removed, and the walls of the tank are allowed to set and harden. The drain pipe extension I is then cut off at the desired point below the top of the tank to provide the exit for the drain pipe.

As shown, the smoothing device consists of a vertical tubular elongated hub I2 of a size to rotatably fit on the drain pipe extension I and of a length slightly greater than the height of the circular wall I 0 of the tank. Arms l3 and I4 are fixed to and radiate from the hub I2, one above the other, the arm I l being on the lower end of hub I2 and constituting the element for smoothing the upper surface of the bottom wall II of the tank. Fixed to and depending from the outer end portion of the arm I3, which is fixed to the upper end of hub I2, are smoothing bars I5 and It for the inner and outer surfaces of the circular wall III of the tank. The arm I4 has its outer end attached to the lower end of bar I5, and said arm I4 and bar I5 may be inclined so that the bottom wall II may increase in thickness outwardly from its center and the wall III may decrease in thickness upwardly, as shown. The bar I6 may be radially adjustable, as at I 1, relative to bar I5, to permit varying the thickness of wall Ill. Also, arms I3 and I I may be adjustable in length, as at I8 and I9, to permit use of the smoothing device for tanks of different diameters. It will be evident that by grasping the outer end of arm I3, the smoothing device may be rotated completely about the extension I to smooth the surfaces, as described.

From the foregoing description, it will be seen that I have provided a method and apparatus for effectively carrying out the stated objects of the invention.

What I claim is:

1. The herein described method of constructing an outdoor circular concrete water tank, which consists of first forming a circular recess in the ground, then laying a drain pipe in the ground radially of the recess and providing the pipe with a vertical extension centrally of the recess, placing successive layers of concrete or mortar-like consistency one upon the other at the margin of said recess to form the circular wall of the tank without the aid of forms or molding means, then placing a further layer of the concrete in the recess to form the bottom of the tank, successively shaping and smoothing the inner and outer surfaces of the first-named layers before the latter hardens, bysmoothing barsrotatable about said drain pipe zextension, andrsmoothing the upper surface of said further layer before the latter hardens by means of a smoothing arm rotatable about said pipe extension with the smoothing bars. 1

2. The herein described method of'constructing an outdoor circular concrete water tank, which consists of first forming a circular recess in the ground, then laying adrain pipe -1in=the ground radially of the recess and providing the pipe with a vertical extension centrally of the recess, placing successive layers of concrete of mortar-like consistency'oneupon the other'atthe margin of said recess-t 'form the circular wall-of the tank without the aid-of forms or molding means, then- -placingafurther layer -ofthe concrete int-he recess to=form-the bottorn of the tank, successively shaping andsmooth ng theinnerand outer surfaces of*the first-named layers before the latter hardens by snloot-hin bars rotatable about said drain -pipe-extension, and smoothing the upper-surface of saidiurther layer before the latter hardens by means of ,ais-moothing arm rotatable about said pipe 'extensionywith the smoothing bars, and-cutting off-"said extensionso as to leave the lowerportio'n thereof to serve as the inlet to thedrainpipe.

3. device, for shaping and smoothing the inner and outer surfaces; of successive layers of concrete ,plaoedtoiorm the circular wall "of, a tank, comprising a vertical pivot adapted, to be placed at the center of the tanlgan elongated tubular hub rotatably fitted upon the vertical pivot, anarm rad atin m ndfi edi ithe said.

hub, spaced inner and outer smoothing bars depending from said arm and substantially corresponding in lengths to the height of said circular wall, and a second lower arm radiating from said hub and connected to the lower end of the inner smoothing bar to smooth the upper urface of a layelg of concrete placed to form the bottom of the ,an

4. :A :device for shaping and smoothing the inner and outer surfaces of successive layers of concrete placed to form the circular wall of a tank, comprising a vertical pivot adapted to be placed at the center of the tank, an elongated tubular hub :rotatably fitted upon the vertical pivot, n arm radiating from and fixed to the said "hub, spaced inner and outer smoothing bars depending :irom sai-darm, and substantially corresponding in length to the height of said circular wall, and a second lower arm radiating from said hub and connected to the lower end of the inner smoothing bar-to smooth the upper surfaceoi a layer ofconcreteplacedto form'the bottom of the tank, said arms being adjustable in length.

FRANK PARRETT.

REFERENCES CITED The following; references are of" record in the file ofthis patent:

UNITED STATES PATENTS Germany Apr. 23, 1912 

